Self-lubricating brush for electrical apparatus



Jul 1927.

y c. E. CHAPIN .SELF LUBRICATING BRUSH FOR ELECTRICAL APPARATUS F1 7. Charles his fl btmegw Filed Nov. 2. 1920 Patented July 12, 1927.

v UNITEDASTATES PA 1,635,257, TENT OFFICE.

CHARLES E. c ArIN. or GREENWICH, CONNECTICUT; FRANKLIN G.- CHAPIN, AND ROBERT c. GLAZIER nxnourons or SAID CHARLES E. CHAPIN, DECEASED.

, sELF- UBRIcA'rIN BRUSH FOR ELECTRICAL APPARATUS.

Application flledNovember 2, 1920. Serial No. 421,267.

This invention relates to brushes for use with electrical apparatus and is herein shown as embodied in a small commutator brush of the wire gauze type such as are employed with small electric motors, for exam; ple, those used in operating electric horns. it will be understood however, that theinvention is not restricted to the illustrated embodiment nor to the uses herein set forth, and that the invention is of general applicahility in the art to which it relates.

A general object of the invention is to provide means for preventing the scratching of the commutator or other contact surfaces by the ends of the conducting wires of brushes such as are used withelectrical apparatus without interfering with the effectiveness of the brushes for the purposes for which they are intended. I

The invention aims further to improve the general construction of electrical brushes, and particularly brushes of the wire gauze type, to render them not only less injurious to the surfaces with which they come in contact, but also more eflicient and more durable.

Otherobjects and important features of the invention will appear from the following description and claims when considered in connection with the accompanying draw ings, in which Fig. 1 is a view of a strip of gauze from which the novel brush of the present invention is to be formed, after this stri of gauze has been coated with lead in accor ance with the novel. process of brush manufacture, which also constitutes a part of the present invention; Y

Fig. 2 is an edge view shown in Fig. 1;

Fig. 3 is a magnified end view of the gauze shown in Fig. 1 showing the mode of coiling to form the brush;

Fig. 4 is a side view of the coiled gauze before ithas been compressed into the final form of the brush;

Fig. 5 shows the completed brush formed I by compressing in a die the form shown in Fig. 4, this figure showing also the holder end of the brush treated with solder to keep the material from uncoiling;

Fig. 6 is an end view of the contact end of the brush; and

Fig. 7 is an end view of the holder end of the brush. v

of the strip of gauze as shown at 6 in Fig. 5,

In making one form of the novel brush of the present invention in accordance with the process which constitutes a part of the present invention, a strip of gauze 2, preferably cut on the bias in the manner shown in F ig. 1 and preferably of the outline shown inFig. 1, is first treated with a soldering solution, at least throughout the part which it is desired to coat, in order to clean its surface and provide a suitable flux for the material with which the gauze is to be coated, and the strip is then dipped into a bath of molten lead for perhaps three-quarters of its length, a sufficient length of untreated gauze being left beyond the part 4, which has thus been coated with lead, to form a covering outside the coated portion when the gauze has been coiled into brush form as shown in Figs. 3 and 6 of the drawings. The gauze thus treated with a soldering solution and dipped into a bath of pure lead will. not only have its mesh substantially completely filled with lead, but the lead will. form a coating over each of, the wires of the gauze as far as the gauze has been immersed in the lead.

f \Vhen a gauze thus treated is coiled in the manner shown in Fig. 3 or in a similar manvner, so that the part coated with lead forms the center of the coil and the uncoated part forms the cover, and the coil is then compressed'into brush form as shown in Fig. 5, it has been found that the lead which fills the interstices between the wires of the wire mesh, of which the conducting part of the brush is formed, not only prevents these wires from digging into the coinnilutator or other contact surface which the brush engages, but the lead itself forms a lubricant which tends to prevent such scratching and to facilitate the relative movement of the surfaces without interfering with the electrical conductivity of the brush.

Although the compression of the brush to the form shown in Fig. 5 in a die tends to make it substantially solid and not liable to open out, in order further to insure the permanency of the brush construction the end of the brush remote from the cOntact end is preferably dipped into molten solder. which serves to fasten together the coils. Moreover, the brush is preferably so coiled that the point of the untreated part of the gauze comes at the end remote from the contact end and this point is thus secured against unwinding and unravelling by the solder.

l lxperin'ienthas shown that a brush of this character having its interstices tilled with pure lead is apparently superior to one in which the interstices have been tilled with a solder con'iposed oi alloy in which lead is predominant, even when the lead constitutes as much as 903 of the alloy, but it will he understood that the inrcntion in not restricted to the use ot lead alone and that it embraces any sot't metal or alloy which will produce the desired results.

lVhat I claim as new is:

l. The process of making a. brush for use with electrical apparatus, which consists in treating a sheet of gauze from which the brush is to be formed with a soldering solution, dipping the gauze into a bath of molten lead thereby causing it to be coated and to have its mesh substantially filled with lead throughout the part that has been dipped, then rolling the treated gauze into a tightly coiled cylinder and moulding it under pressure to the desired brush shape.

'2. The process of making a brush tor use with electrical apparatus, which consists in treating a strip of wire gauze from which the brush is to he formed with soldering solution, then dipping the gauze into a bath of molten lead to such a depth that sutticient gauze will be left. untreated to cover the outside of the brush. rolling the gauze into a tightly coiled cylinder with the lead coated portion inside and the uncoated portion outside and moulding the cylinder thus formed under pressure into a brush ol the desired shape and size.

3. The process of making a brush for use with electrical apparatus, which consists in treating a strip of wiregauze from which the brush is to be formed with a soldering solution, then dipping the gauze into a bath of molten lead to such a depth that sutiicient; gauze will be left untreated to cover the outside of the brush, rolling the gauze into a tightly coiled cylinder with the lead coated portion inside and the uncoated portion outside and moulding the cylinder thus formed under pressure into a brush ot the desired shape and size and then dipping the holder end of the brush into solder to secure the gauze in its coiled condition.

el. A brush for use with electrical apparatus comprising a series ol? grouped wires arranged in brush term and having lubricating metal applied to the wires on the interior ol the brush and the wires on the exterior of the brush tree of such metal.

5. A brush tor use with electrical appara- 0 tus comprising a foundation of wire gauze made into brush form and having lubricating metal applied tothe wires 01? the gauze on the interior of the brush and the "wires oi the gauze on the exterior of the brush 5 free from such metal.

6. The process of making a brush for uSe with electrical apparatus, which comprises applying a lubricating metal to a sectionlo't wire screen so as to cover the wires of the screen and to fill the meshes thereof and folding and compressin said screen to form a brush and to cause the lubricating metal to fill the interstices between adj acent; wires of the screen at least in a substantial portion of the brush.

7. The process of making a brush for use with electrical apparatus which comprises applying a lubricating metal to a series of grouped wires so as to cover the wires, and 30 compressing said wires to form a block and to cause the lubricating metal to till the interstices bet-ween adjacent wires at. lt-ast in a substantial portion of the brush 8. The process of making a brush for use with electrical apparatus which comprises applying a lubricating metal to a portion of wire screen, folding said screen to form a block. covering the same with an exterior layer of uncoated screen and compressing said screen to form a brush.

Signed at New York, this 1st day of November, 1920.

CHARLES E. CHAPIN. 

